The City of Calgary requires mandrel testing on all new installed PVC SDR-35 pipes from 200mm-750mm in size. Thuro completes “Mandrel testing” or “deflection testing” to confirm these pipe installations (PVC) meet City of Calgary design specifications. The mandrel test is performed to check if there is deformation or any lows present in the pipe. Deformations are apparent when the pipe is out of shape (not round) but minor deformations can be difficult to spot in a regular video inspection. If there is an issue with the bedding of a pipe it can cause a sag or low in the line. Sags and low spots create a back-grade that disrupts the normal flow of the line.
During a mandrel test, the physical mandrel is pulled through the sewer line. At the same time, a main line video inspection is completed to view our mandrel test being performed. The video is used to confirm the test is successful or locate the defective area where a mandrel test has failed. The mandrel is designed to a specific size as designated by the City of Calgary. If the mandrel can be pulled through the length of line then the installation meets City of Calgary specifications. It is a simple method, but it works.
If a mandrel doesn’t make it through the line does not meet specification. Mandrel tests are performed as requested post install by the installation contractor as part of QA and QC and the test is also required by the City of Calgary 2 years after the installation for the contractor to get their Final Acceptance Certificate. This confirms that after settling of the ground post construction that the lines hold their shape. This makes Mandrel testing critical to ensuring long-term performance of PVC sewer lines.
Thuro Inc. manufactures mandrel sets for use in The City of Calgary. Each set has a proving ring with unique serial number that is approved for use from the City of Calgary Water Resources department. The light-weight aluminum deflection gauges utilize a nine-fin configuration. This star shaped configuration allows for sewage to pass through when testing live sewers so there are no disruptions to service. The fin sets include steel GO + NO GO proving rings that are used to verify the deflection gauge is within tolerance. In this method of verification, the mandrel is assembled and then the proving ring is slid over the mandrel. There are alternating notches or indents in the ring. If the ring passes over the mandrel on the indented GO notch and does not pass over on the NO GO notch it confirms the mandrel is within tolerance.
Thuro provides testing services to Calgary and the surrounding areas. We have been in business since 1969 which means we have a lot of experience.
Call now to confirm your lines were installed correctly!